Files
py-libp2p/examples/echo/echo.py

121 lines
3.5 KiB
Python

import argparse
import multiaddr
import trio
from libp2p import (
new_host,
)
from libp2p.crypto.secp256k1 import (
create_new_key_pair,
)
from libp2p.custom_types import (
TProtocol,
)
from libp2p.network.stream.net_stream import (
INetStream,
)
from libp2p.peer.peerinfo import (
info_from_p2p_addr,
)
PROTOCOL_ID = TProtocol("/echo/1.0.0")
MAX_READ_LEN = 2**32 - 1
async def _echo_stream_handler(stream: INetStream) -> None:
# Wait until EOF
msg = await stream.read(MAX_READ_LEN)
await stream.write(msg)
await stream.close()
async def run(port: int, destination: str, seed: int | None = None) -> None:
listen_addr = multiaddr.Multiaddr(f"/ip4/0.0.0.0/tcp/{port}")
if seed:
import random
random.seed(seed)
secret_number = random.getrandbits(32 * 8)
secret = secret_number.to_bytes(length=32, byteorder="big")
else:
import secrets
secret = secrets.token_bytes(32)
host = new_host(key_pair=create_new_key_pair(secret))
async with host.run(listen_addrs=[listen_addr]), trio.open_nursery() as nursery:
# Start the peer-store cleanup task
nursery.start_soon(host.get_peerstore().start_cleanup_task, 60)
print(f"I am {host.get_id().to_string()}")
if not destination: # its the server
host.set_stream_handler(PROTOCOL_ID, _echo_stream_handler)
print(
"Run this from the same folder in another console:\n\n"
f"echo-demo "
f"-d {host.get_addrs()[0]}\n"
)
print("Waiting for incoming connections...")
await trio.sleep_forever()
else: # its the client
maddr = multiaddr.Multiaddr(destination)
info = info_from_p2p_addr(maddr)
# Associate the peer with local ip address
await host.connect(info)
# Start a stream with the destination.
# Multiaddress of the destination peer is fetched from the peerstore
# using 'peerId'.
stream = await host.new_stream(info.peer_id, [PROTOCOL_ID])
msg = b"hi, there!\n"
await stream.write(msg)
response = await stream.read()
await stream.close()
print(f"Sent: {msg.decode('utf-8')}")
print(f"Got: {response.decode('utf-8')}")
def main() -> None:
description = """
This program demonstrates a simple echo protocol where a peer listens for
connections and copies back any input received on a stream.
To use it, first run 'python ./echo -p <PORT>', where <PORT> is the port number.
Then, run another host with 'python ./chat -p <ANOTHER_PORT> -d <DESTINATION>',
where <DESTINATION> is the multiaddress of the previous listener host.
"""
example_maddr = (
"/ip4/127.0.0.1/tcp/8000/p2p/QmQn4SwGkDZKkUEpBRBvTmheQycxAHJUNmVEnjA2v1qe8Q"
)
parser = argparse.ArgumentParser(description=description)
parser.add_argument("-p", "--port", default=0, type=int, help="source port number")
parser.add_argument(
"-d",
"--destination",
type=str,
help=f"destination multiaddr string, e.g. {example_maddr}",
)
parser.add_argument(
"-s",
"--seed",
type=int,
help="provide a seed to the random number generator (e.g. to fix peer IDs across runs)", # noqa: E501
)
args = parser.parse_args()
try:
trio.run(run, args.port, args.destination, args.seed)
except KeyboardInterrupt:
pass
if __name__ == "__main__":
main()